But 10 years ago the Philippine investors paid $50 million for their long-term leasehold (another party owns the land).

But when the market sank and key tenants moved, the bank consortium that held the mortgage on the Kaufmans' long-term leasehold took it back.

(In the case of a long-term leasehold, it is common for the fee owner to exercise some control over the nature of any building erected.)

In 1993, the long-term leasehold was declared in default and the Travelers Insurance Company foreclosed on the mortgage.

And last month Kinson Properties closed on the purchase of the long-term leasehold to the distinguished if tattered 1.1-million-square-foot skyscraper at 40 Wall Street.

Millennium would not buy the parcel outright from the owners, a group that includes Arnold R. Sollar, but would enter instead into what Mr. Jeffries called a "very long-term leasehold."

In forming their demonstration project, they pooled their funds to purchase land at "Stapleton's pasture" on the eastern shore of Mobile Bay and then divided it into a number of long-term leaseholds.

Mr. Cohen, who is also president and chief executive of the Cohen Brothers Realty Corporation, bought the long-term leasehold on the Manhattan Theater site in 1998 and on the D.&D. Building in 1996.

SL Green, a real estate investment trust based in Manhattan, said the purchase agreement covered the acquisition of 1466 Broadway and the long-term leaseholds of 25 West 43d Street and the Graybar Building, at 420 Lexington Avenue, a total of 1.8 million square feet of office space.